Re: Sparc64-2.5.72: A Serious Time Problem

george anzinger (george@mvista.com)
Wed, 18 Jun 2003 02:12:39 -0700


B. D. Elliott wrote:
> There is a serious bug in setting time on 64-bit sparcs (and probably other
> 64-bit systems). The symptom is that ntpdate or date set the time back to
> 1969 or 1970. The underlying problems are that stime is broken, and any
> settimeofday call fails with a bad fractional value. Ntpdate falls back to
> stime when settimeofday fails.
>
> The settimeofday problem is that the timeval and timespec structures are not
> the same size. In particular, the fractional part is an int in timeval, and
> a long in timespec. The stime problem is that the argument is not an int,
> but a time_t, which is long on at least some 64-bit systems.
>
> The following patch appears to fix this on my sparc64.

Looks reasonable. The stime problem must have been there for some
time but I just introduced the timespec/ timeval thing. Someday soon
I will get this 64-bit long/int thing down. I promise :)

-g
>
> ===================================================================
> --- ./kernel/time.c.orig 2003-06-16 22:36:04.000000000 -0700
> +++ ./kernel/time.c 2003-06-18 00:00:43.000000000 -0700
> @@ -66,7 +66,7 @@
> * architectures that need it).
> */
>
> -asmlinkage long sys_stime(int * tptr)
> +asmlinkage long sys_stime(time_t * tptr)
> {
> struct timespec tv;
>
> @@ -162,13 +162,15 @@
>
> asmlinkage long sys_settimeofday(struct timeval __user *tv, struct timezone __user *tz)
> {
> + struct timeval user_tv;
> struct timespec new_tv;
> struct timezone new_tz;
>
> if (tv) {
> - if (copy_from_user(&new_tv, tv, sizeof(*tv)))
> + if (copy_from_user(&user_tv, tv, sizeof(*tv)))
> return -EFAULT;
> - new_tv.tv_nsec *= NSEC_PER_USEC;
> + new_tv.tv_sec = user_tv.tv_sec;
> + new_tv.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC;
> }
> if (tz) {
> if (copy_from_user(&new_tz, tz, sizeof(*tz)))
> ===================================================================
>

-- 
George Anzinger   george@mvista.com
High-res-timers:  http://sourceforge.net/projects/high-res-timers/
Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml

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